Apparatus for detecting the running of railway vehicles or the like

ABSTRACT

An electromechanical railway traffic controller device for detecting the passage of railway vehicles or trains comprising an electric rotary switch with a vertical shaft pivoted to the switch actuating lever consisting of a long arm lying adjacent to the rail for being hit by the wheel flange of a railcar; and a damping arrangement for slowing down the spring-biased return motion of said arm to prevent said arm of being hit by every wheel of the vehicle or train.

United States Patent Paulve I i Q 1 [54] APPARATUS FOR DETECTING TI'IE RUNNING OF RAILWAY VEHICLES OR THE LIKE I Muy, France Filed: Aug. 19, 1970" Appl. No.: 64,981

Foreign Application Priority Data Aug; 19, 1969 France ..6928448 [52] US. Cl..... .......24.6/248, 200/6l.41, 200/153 LB Field of Search ..200/153 LB, 153 P, 61.41;

References Cited UNITED STATES PATENTS 1,668,267 5/1928 Colas ..246/248 Inventor: Marcel Luc Amedee Paulve, 83 Le Int. Cl. ..B61I 13/02 ..llllllllll g" as; 7 3,702,396 14s] Nov.'7, 1972 FOREIGN PATENTS OR APPLICATIONS 1,054,990 2/1954 France ..246/248 Primary Examiner-Gerald M. Forlenza Assistant, Examiner-George H. Libman Attorney-Nolte and Nolte [57] ABSTRACT An electromechanical railway traffic controller device for detecting the passage of railway vehicles or trains comprising an electric rotary switch with a vertical shaft pivoted to the switch actuating lever consisting of a long arm lying adjacent to the rail for being hit by ithe wheel flange of a railcar; and a damping arrange ment for slowing down the spring-biased return mo- 8 tion of, said arm to prevent said arm of being hit by ievery wheel of thevehicle or train. 7

12 Claims, 7 Drawing Figures;

PATENTED 71972 3 7 O2 396 sum 1 or 4 PAIENTEDunv 11m 3.702.396

' sum 3 0F 4 I FIG. 2A 46 APPARATUS FOR DETECTING THE RUNNING OF RAILWAY VEHICLES OR THE LIKE The present invention concerns and has essentially for its object improvements to electromechanical apparatus for detecting the running of vehicles on doubleor single-track railways or the like, intended to reveal the passage of a rolling vehicle, a train or a set of railway carriages or wagons or generally all traffic and running motions occurring on a given railway, in order to transmit, produce or emit a corresponding electric signalor impulse, in particular by closing and/or opening one or several electric circuits, for instance for the announcing of trains, especially at level-crossings, the automaticclosing of signals, the operation of the stationary electric contacts of the railway, and for all the electrical actions to beproduced or started by a running on the railway,as well as for any other safety or signalling function. It also concerns the various applications and uses of the said device and the systems, as-

semblies, circuits, railways, equipments and installations or plants provided therewith. [There is already known, for instance according to French Pat. No. 1,054,990, a monitoring and remotecontrol apparatus of this type intended to be fastened laterally to a rail or to a stretch of rails, particularly on the internal side of the railway, especially by means of a universal fastening and supporting device such asdisclosed for instance in French Pat No. 1,452,264. This known apparatus comprises a rotary electric switch whose rotor shaft, the axis of rotation of which is substantially vertical, is hinged by means of a substantially horizontal hinge pin to a reversible rotary pivoting control lever of the said rotor, serving to actuate the said apparatus and comprising an exposed long arm whose end is located in proximity to the running surface of the rail and is intended to'be hit by the flange of the wheel of a rolling vehicle running on the railway considered. This lever is guided positively so as to be-displaceable obliquely downwardly, under the action of the impact, from a normal upper position of. rest or neutral position, symmetrically with respect to a vertical plane perpendicular to the railway, respectively for both mutually opposeddirections of running. To this end, the said lever passes through-a forced-guiding slot having an angular configuration substantially in the shape of a reversed V substantially symmetrical with respect to a vertical plane extending transversely or perpendicularly to the railway. The lever is besides movably connected, in particular by means of a sliding hinged joint, with the piston rod of an oil, hydraulic-fluid of like dash-pot forming a damping, slowing down or braking device serving to retard the automatic return of the said lever to its central upper position of rest from which it was moved under the action of the impact in the present direction of running. This dash-pot piston isv adapted to slide vertically in a cylindrical chamber of the said rotor shaft and is pushed backor urged perm anently by a coaxial helical return spring in the rising direction of the said lever. This slow or delayed return of the lever serves to ensure electrical switchings by closing or opening contacts during a given period and to avoid that the control lever be actuated by all the wheels of the vehicle (locomotive, wagon, rail-car, carriage, etc.) or of a train following the first wheel having hit the said lever. t

The aforesaid apparatus is provided with an oil sucking and check or non-return valve for thedash-pot, the piston of which is traversed axially by a restricted escape channel having a calibrated throttlingorifice providing a substantially constant, determined and selectively variable flow by means of a regulating needle or the like.

This known apparatus has several drawbacks. In particular, the sliding hinged joint ensuring the connection of the control lever with the dash-pot piston is generally liable to wear or rapid deterioration owing to the impacts applied during normal working. On the other hand, the action of the said calibrated orifice may be insufficient to achieve a sufficient retarding effect and escape flow may be produced by a thermal variation of the viscosity of the oil or the hydraulic fluid employed in the dash-pot owing to the corresponding change in temperature. Lastly, in the known apparatus, the case of the electric switch is mounted inside the carter of the apparatus at an intermediate, point of the aforementioned rotary vertical movable assembly, in particular above the dash-pot, between the latter and the connection of the rotary movable assembly with the said control lever, thus rendering the electric switch difficult of access for maintenance, supervision or repair.

The invention has for its main purpose to remedy the above-mentioned drawbacks by creating an apparatus having a sturdy construction enabling ready access to all the internal pieces or parts in case ,of need, offering satisfactory; stable, reliable and efficient operation, long life and easy maintenance, and enabling very rapid mounting, adjustment and replacement. Moreover, the apparatus is efficiently protected against bad weather and the influence of external mediums. To this end, the apparatus according to the invention is characterized in that the aforesaid lever is hinged at an intermediate point to the aforesaid rotor shaft and its movable connection with the piston rod of the said dash-pot is achieved by the meshingof a vertical rack solid with the said piston rod with a matingtoothed segment solid with the short arm of the said lever and centered on the horizontal hinge pin of the latter, while the aforesaid return spring is composed of at least two concentric component helical springs wound respectively in opposite directions, surrounding the said piston rod and bearing at one end against the top wall of the cylinder or the cylindrical chamber of the dash-pot solid with the said rotor shaft, and at the other end against the said piston, preferably through the medium of a thrust bearing or the like interposed between the said set of springs and the said piston. I

Such an arrangement offers the advantage of enabling to obtain accurate and positive or non-slip drive of the piston rod Moreover, the presence of the said thrust bearing between the return springs and the piston (solid with the rack) serves to render the said rack independent of the return springs by disconnecting it from the latter. Indeed, if the return springs were bearing directly against the said piston, thus establishing a connection through direct frictional contact with the latter, in case of vibrations or impacts undergone by the said springs which are wound in mutually opposite directions, one

in vertical translation.

the toothed segment, through the medium of the frictional contact with the piston, thus involving a risk of seizing of the rack-and-toothed segment gear as a result of the jamming of the meshing teeth of the latter.

According to another feature of the invention, the apparatus comprises a throttle valve provided with an obturating ball, of a type known per se, loaded with a spring whose calibration is adjustable, and mounted in the escape channel of the said dash-pot downstream of the said calibrated orifice in the direction of the escape flow, the aforesaid suction and check or non-return valve or the said ball valve comprising means ensuring a given small permanent escape, which consists preferably of fluid-tightness defects such as hollows in the seat for the obturating member. of the said suction valve or the saidcheck valve, for instance of a conical or spherical annular bearing surface of the seat of the said ball valve, provided with angularly spaced imprints forming substantially plane facets or the like extending all over the width of the said bearing surface. Such an arrangement offers the advantage of obviating the apparition of untimely or unforseen passive resistances between the portions in relative motion during the operation of the apparatus. Indeed, in the absence of such a permanent possibility of auxiliary escape in the seat of either the reducing ball-valve or the suction and check or non-return valve, the automatic motion of return of the lever to its medial upper position of rest may be possibly prevented untimely by the unforeseen apparition of accessive passive resistances between the parts in relative motion, which resistances would then absorb the useful force of the return springs, thus causing the closing of the ball valve, since the pressure of the oil forced out by the dash-pot piston under the action of the said springs would be insufficient to raise the said ball. The mechanical system would then be hydraulically jammed in an intermediate position. Owing to the presence of means enabling the auxiliary escape independently of the open or closed positionof the ball valve, the oil may continue to escape through the said auxiliary escape means even when the ball is in a closing position, so that the motion of return of the movable mechanism to its normal position of rest is not interrupted but on the contrary ensured continuously.

According to another feature of the invention, the needle associated with the aforesaid calibrated orifice displays an evolutive longitudinal profile terminating the central rod of a thermostatic device known per se, for instance according to French Pat. No. 1,219,389, mounted in the said escape channel and automatically regularizing the rate of flow of the fluid stream by way of differential compensation as a function of the thermal variations of the viscosity of the working hydraulic fluid, the said calibrated orifice constituting preferably the inlet adjutage of a pressure-reducing chamber adjacent to the said ball valve upstream of the latter. Such an arrangement offers the advantage of enabling automatic regulation of the rate of escape flow and, consequently, of the delaying or duration of the deferred rising of the control lever (for instance on the order of 15 seconds), maintaining the latter practically constant within wide limits of temperature variations, for instance in the range extending from to'+70 C.

Owing to, the use of the abovementioned thermostatic device, it is interesting to provide the said permanent auxiliary escape on the said suction and check or non-return valve rather than on the reducing ballvalve, in order to render the said auxiliary escape independent of the risks of obturation or accidental clogging of the passageway for the said needle of the thermostatic device. I

According to still another feature of the invention, the piston of the said dash-pot is provided on its peripheral lateral surface with spaced escape slots or like recesses opening at one end into the end face of the said piston which is on the side of the said return springs and extending in the direction of the opposite face over a length smaller than that of the said piston, so as to leave on the latter a smooth zone, while the ball of the said cylindrical chamber of the dash-pot widens towards its end location on the side opposite the said return springs, a short distance from the location of the end of the stroke of thesaid pistonpushed by the said springs, soas to uncover the said slots in order to interconnect the spaces located respectively on eitherside of the said piston. The said slots are advantageously parallel with the axis of the dash-pot piston, i.e., substantially vertical.

Such an arrangement is advantageous in that it enables to first achieve a slow return of the control lever in a time judiciously determined to conveniently ensure the electrical switchings by always following one and the same trajectory up to its initial position, and then a rapid return of the said lever at the end of its travel owing to the additional escape of oil createdat the periphery of the piston in proximity to the end of the downward stroke of the latter, when the said piston penetrates into the lower widened portion of its cylindrical chamber.

The invention will be better understood and other objects, characteristics and advantages thereof will appear as the following description proceeds, with reference to the appended drawings given solely by way of example illustrating one form of embodiment of the invention and wherein:

FIG. 1 is an external side view of theapparatus according to the invention, mounted on the rail of a railway:

FIG. 2 shows a fragmentary view, to a larger scale, of the said apparatus, in section along a plane passing through its vertical axis, partially broken away and illustrating the control lever in initial upper position of rest; FIG. 2A shows details thereof FIG. 3 is an isolated axial sectional view of the electric switch, upon the line III-III of FIG. 4 and with parts broken away;

FIG. 4 is atop view, partially in section, of the said electric switch: 1

FIG. 5 is an enlarged detailed view, in axial section upon the brOken line VV of FIG. 6, of the seat of the aforesaid reducing valve with its obturating ball;

FIG. 6 is a top view of the sealing bearing surface of the said seat.

According to the example of embodiment illustrated in FIG. 1, the apparatus of the invention, denoted generally by the reference numeral 1, is secured to the rail 2 of a railway on the internal side of the latter, by means of a support 3 adapted to be secured to the flange or base 4 of the rail. The support 3 is for instance of the type shown in FIG. 2 of French Pat. No. 1,452,264 and which comprises a pair of respectively internal and external clips or clamping jaws Sand 6 hooking or gripping the respective opposite lateral edges'of the rail flange 4, the said clips being arranged in mutually confronting relationship and mounted so as to freely slide on a transverse threaded rod 7 passing on the rail 2. The apparatus 1 is suspended by two independentsymmetrical brackets 8 secured respectively on each side to the body of the apparatus, for instance by means of three screws, and only one of which is seen in FIG. 1. Each bracket is provided at its 'free end by a substantially vertical column 9 adapted to be secured by way of clamping against avertical-anglea or cornerpiece or the like 10 solid with the internal clip 5, the said two corner-pieces being arranged substantially symmetrically with respect to a vertical plane perpendicular to the rail. The two columns 9 are secured by means of a mating clamp or clamping nut-plate applied simultaneously against the two columns 9 and provided with a tapped horizontal central hole into which is screwed one end of the threaded rod 7, the other end of which carries a nut 11 tightened against the external clip 6 through the medium of an interposed setof Belleville washers orthe like so as to ensure a constant resilient clamping force. The support 3 thus enables to readily adjust the height of the apparatus 1 by way of vertical sliding of the fastening columns 9 in the clamping assembly 10 so as to bring the end of the control lever 13 of the apparatus to a correct level and to the required relative position and distance from the rolling plane of the rail 2.

According to FIG. 2, the apparatus 1 comprises a closed carter 14, for instance of light alloy, on which are bilaterally secured the aforesaid brackets 8 and which is sealingly closed at itstop by a removable cover 15 secured to the Carter 14 by screws or the like through the medium of interposed sealing rings or annular sealing gaskets or packings. The carter forms in its internal cavity an oil or likehydraulic-fluid reservoir filling it at least partially.

Beneath the carter 14 is placed the case of the electric switch 16, made for instance from synthetic material and secured sealingly and removably against the bottom of the carter l4.

The movable assembly of the apparatus is mainly constituted by the vertical rotary shaft 17 of the rotor 18 forming the mobile armature of'the electric switch 16. The shaft 17 is hollow and mounted rotatably in two sealed rolling bearings, for instance roll bearings, 19 and 20, provided respectively in the upper cover 15 and the bottom wall 21 of the carter 14. The shaft 17 is composed of two, respectively upper and lower tubular shaft elements, 22 and 23, arranged coaxially and each in mutually opposed directions. The said piston is advantageously constituted by a shouldered annular counter-plate 30 mounted on a shouldered surface of the lower end of the piston rod 31' and by a clamping nut or the like 32 screwed onto the threaded lower end of the piston rod 31. The two sealing gaskets 28, 29 are joined side by side by their horizontal annular portions penetrating into the shoulder of the said counter-plate so as to be clamped between the counter-plate 30 and the nut 32. In order to improve the anchoring of the sealing gasket in the piston 27, the counter-plate 30 and the nut 32 are advantageously provided with several annular, concentric and radially spaced grooves on their surfaces which are in contact with the said sealing gaskets, so that the matter constituting the latter is forced into the said grooves under the action of the clamping. t

It is then advantageous to provide the previously mentioned additional escape slots at 35 on the cylindricallateral surface of the lower sealing gasket 29. In proximity to or at the level of the downward stroke end of the piston 27, such as shown in FIG. 2, the internal wall of the cylindrical chamber 26 widens radially at 36 in order to uncover the additional escape slots 35. The cylindrical chamber 26 is divided transversely, in a manner known per se, by the piston 27 into two, respectively upper and lower, variable-volume sections 37 and 38. The upper section contains the said pair of concentric helical springs 39, the spires of which are wound in mutually opposite directions and which coaxially surround the piston rod 31.

The upper section 37 communicates permanently with the internal cavity or space 40 of the carter 14 through one or several passage orifices 41 passing through the wall of the chamber 26. The said passage orifices are located preferably substantially in straddling relationship to thelevel of the liquid surface 42 of the oil 43 sealing partially the carter l4 and in which the whole lower portion of the movable assembly 27 is immersed.

The lower section and end of the working chamber 26 are closed by the lower shaft element 23 which is provided for this purpose, at its lower end, with an end flange 44 forming the bottom of the lower section 38' and secured at the end of the upper shaft element 22.

The piston rod 31 is tubular, i.e. entirely traversed by a central longitudinal bore 45 forming an escape channel for the said dash-pot and communicating permanently with the lower section 38. This piston rod is slidingly mounted in the axial bore 24 of the upper shaft element 22. A sufficient free space 46 is provided in the cover 15 above the upper end of the shaft 17 ending therein, to enable the ascending motion of the piston rod 31 in the direction of the upward stroke end of the piston 27. The upper portion of the piston rod 31 comprises a vertical rack portion 47 which permanently meshes with a mating toothed segment 48 solid with the control lever 13 which is hinged to the upper shaft element 22 by means of a substantially horizontal hinge pin 49 concentric with the toothed segment 48. To this end, the internal end of the lever 13 is arranged between the legs or prongs of a hinge yoke 50 carrying the hinge pin 49 and solid with the upper shaft element 22. The tubular wall of the upper shaft element 22 is provided with a lateral opening .51

for the passage of the toothed segment 48 meshing with the rack 47.

The pair of concentric return springs 39 bears byits upper end against the top wall of the cylindrical chamber 26 and by its lower end against the upper face of the piston 27, preferably through the medium of a rolling thrust bearing52, for instance a roller or needle bearing.

The flange 44 of the lower shaft element 23 is secured on the upper shaft element 22, preferably by way of clamping in a counter-sunk recess of the latter by means of an annular capn ut 53 screwed onto the said upper shaft element. The flange 44 is advantageously provided with one or several suction and check or non-return valves 54, upstream of which is placed a filter or the like 55 possibly mounted in the cap-nut 53. The'said suction valves are advantageously constituted by a series of circumferentially spaced holes 56 passing through the flange 44 and for instance uniformly distributed about the vertical axis of the said flange. The cover or obturating member of the valves is constituted for instance by a thin annular flexible plate or a supple lamina in the shape of a disk or washer 57 mounted on the upper end of the lower shaft element 23 and adapted to be applied resiliently onto the holes 54 so as to obturate the same, the said resilient plate or lamina being adapted to rise in order to uncover the said holes under the action of an ascending pressure of fluid. The cap-nut 53 leaves about the lower shaft element 23 an annular opening 58 interconnecting the holes 54 with the oil 43 of the cavity 40 through the medium of the filter 55.

k In the upper end of the escape channel 45 constituted by the central bore of the piston rod 31 are located the escape valve 59 and the calibrated orifice 50. The said escape valve and calibrated orifice are advantageously combined to form a single device constituted by a reducing ball-valve or the like, the body 61 of which is screwed onto the upper end of the piston rod 31. The fluid-tightness between the external wall of the body 61 and internal wall of the bore 45 is ensured by O-rings or annular rings or seals 62 mounted in corresponding grooves of the body 61 and in frictional contact with the bore 45. This frictional contact serves at the same time as a means of locking the body 61 screwed in the bore 45. The obturating member is constituted, in a manner known per se, by a ball 63 mounted in the body 61 and adapted to be applied onto a sealing seat 64 located in the longitudinal passageway passing right through the body 61 coaxially with the bore 45. The said ball is loaded with a spring 65 bearing upon a threaded plug 66 slipped onto the upper end of the body 61 and traversed by a coaxial escape passageway opening into the space 46. The initial force or compression of the spring 65 is thus adjustable by the bore 45 of the latter. The tube 68 penetrates and extends with a given annular play into the bore 25 of the aforesaid lower shaft element 23, possibly down to the vicinity of the lower end of the latter, hermetically obturated for instance by a threaded plug or the like 69. Oil inlet orifices are provided in the lateralwall of the portion of the tube 68 located inside the lower shaft element, so that the lower section 38 of the cylindrical chamber 26 communicates permanently with the interior of the tube 68 and, therefore, the escape channel 45 through its holes 70.

The thermostatic device mentioned at the beginning is constituted by the combination of the pressurereducing valve 59 and the calibrated adjutage 60 with a thermostatic member 71 constituted by a vertical rod mounted coaxially with a certain play in the escape channel 45 by being for instance screwed at its lower end 72 shaped as a threaded head, into the lower end of the tube 68 which it thus obturates at the bottom. The rod 71 advantageously has a cross-shaped transverse section or a section comprising longitudinal grooves, slots or passageways enabling the passage of the ascending flows of oil entering into the tube 68 through the orifices 70. The rod 71 may be made from any suitable material with a high co-efficient of expansion, for instance a synthetic material, and carries at its upper end a substantially cylindrical needle or the like 73 which is for instance fitted, screwed or sunk by way of moulding into the upper end of the rod 68. The cross-shaped section of the rod 71 facilitates the equalization of the temperatures of the said thermostatic rod and the surrounding liquid. The upper endof the needle 73 penetrates into this calibrated adjutage 60 and is shaped or may have the same diameter as the orifice 60, but is provided with a bevelled face so as to be capable of varying very progressively the flow section of the adjutage 60 when the needle 73 slides in the latter. This system of automatic thermostatic regulation of the rate of flow of a stream of fluid, which is described and illustrated in detail in French Pat. No. 1,219,389 already mentioned, enables to avoid the inconvenience of the usual point screw, the thermal expansion of which may cause complete obturation of the adjutage 60. by becoming jammed on the latter. It protects the rate of flow in the escape channel against all disturbances caused by heat and enables, owing to the pressure-limiting device formed by the ball valve 59 to reduce the pressure drop occurring in the fluid stream passing through the adjutage 60. Owing to such an arrangement and even at a considerable fluid pressure upstream of the adjutage, i.e., in the escape channel 45, a small pressure drop during the passage through the adjutage 60 and, therefore, a small lamination effect may be obtained even in the case of a relatively small escape-flow section. Thus, in particular, any risk of abnormal heating of the liquid as a result of lamination against the walls of the orifice 60 is eliminated. Moreover, much larger fluid-flow sections may be used without however increasing the set rate of flow, owing to the small difference in pressures existing upstream and downstream of the adjutage 60. This device reduces at the same time the risk of obturation of the adjutage 60 by foreign matters or other particles which may happen to be carried by the current of fluid. The pressure-reducing chamber 67 located downstream of the adjutage 60 enables to produce therein a counterpressure which depends on the pressure exerted by the antagonistic spring 65. The relative position of the calibrated adjutage 60 with respect to the needle 73 is adjustable owing to the screwed fixing of the body 61 of the reducing valve.

The apparatus is advantageously equipped with a magnetic purifying device for the oil contained therein, which device is advantageously constituted by a threaded plug or thelike 74 screwed into the lateral wall of the carter 14 through which it passes sealingly below the level 42 of the oil surface. The threaded plug 74 is provided with a magnetic core 75 protruding from the mass of oil and purifying the latter by retaining through magnetic attraction all the magnetic impurities contained in the oil. I

Substantially opposite the orifice 51 is provided an orifice 76 in the lateral wall of the upper portion of the carter 14. In the orifice is mounted a plate 77 provided with a forced-guiding slot in the shape of a reversed V which is traversed by the free arm of the control lever 13. In FIG. 2 this lever is shown in its upper initial position, i.e. substantially above the internal edge of the vertex of the angle formed by the guiding slot 78 in which the said lever is slidingly mounted and which materialized the symmetrical oblique trajectories of the said lever, determined respectively by the two directions of running on the railway considered. In order to facilitate the motion of entry of the lever 13 into one or the other leg of the guiding slot, forming the sides of the angle constituted by the said slot, the lever 13 is advantageously provided, substantially at the level of the, upper edge of the said slot, with a knife-shaped protruding boss 79, the edge of which is substantially parallel with the edge at the vertex of the said angled slot.

In order to ensure fluid-tightness at the outlet for the free end of the lever 13, there is provided a supple or deformable impervious bellows v80, made for instance from rubber, surrounding hermetically the lever 13 and secured to the wall of the carter 14, preferably at the edge of the orifice 76, thus covering the passage opening of the latter. Thebellows is preferably secured outside with respect to the plate 77, thus defining with the latter an enclosed space 81 communicating permanently through passageways or orifices 82, 83 with the oil cavity 40 of the said carter and in particular with the upper end of the outlet channel of the reducing valve 59 through the medium of the space 46 located above the said valve. The lower edge of the orifice 76 or the lowest connection passageway 83 is ad? vantageously located above the level 42 of the free surface of the oil 43 in the carter 14. The periphery of the bellows 80 is advantageously sealingly secured to the edge of the aforementioned passage opening for the lever 13, preferably by way of clamping by means of a sleeve 84 provided with an external thread screwed into the said opening and pressing the peripheral edge of the bellows against a suitable sealing ring mounted in the carter wall. The sleeve 84 also advantageously serves to clamp and secure the plate 77 on the periphery of which the said sleeve bears by pressing it against a corresponding counter-sink or shoulder defining the orifice-76.

As mentioned at the beginning, the suction valve 54 or the pressure-limiting valve 59 are advantageously provided with means creating a permanent auxiliary escape. FIGS. 5 and 6 show these means applied on the reducing valve 59. To this end, the sealing seat for the ball 63 is constituted by a bearing surface 64 in the shape of, for instance, a substantially conical zone in which are provided circumferentially spaced imprints spaced for instance uniformly and having for instance the shape of plane facets converging towards the axis of the conical zone, therefore a substantially trapezoidal shape, and extending over the whole width of the said zone as shown in FIG. 6 where the ball is omitted. When the ball 63 of the valve is in contact with its sealing seat 64 under the action of the spring 65 acting on the said ball through the medium of a cup-shaped bearing member 86 provided with a peripheral flange covering the same, the ball is tangent to the conical zone 64 solely in the conical surface portions 87 separating the facets 85 from one another, while on the facets 85 constituting a recess or hollow there are provided escape passageways between the seat 64 and the ball 63.

The lower shaft element 23 passes sealingly through the bottom21 of the carter 14 and penetrates into the case of the electric switch 16. The latter is for instance of the type described and illustrated in French Pat. No. 1,153,127 or in French Pat. No. 1,252,608. The electric switch comprises a stator or block of electrically insulating material 88 (see FIGS. 2 to 4) provided with an opening 89 in its upper portion and securedby means of vertical studs 90 passing therethrough against the underside of the carter 14 through the medium of interposed annular seals. This contact-carrying stator or block is closed at its bottom by a cover 91 sealingly secured by means of screws 92 on studs 90 through the medium of an interposed O-ring seal. The said cover thus protects the chamber 93 containing the electric contacts against penetration of dust, moisture or snow, the whole assembly being covered by an external protecting casing, hood or cap 94 removably and sealingly secured by means of spring-loaded rocking locks 95 (see FIG. 1) actuated manually, against the lower portion of the carter 14 through the medium of an annular seal. The contact carrying block 88 is provided with terminals 96 arranged in two tiers of four terminals and separated respectively by radial vertical and horizontal partitioning ribs 97 and 98 respectively. The electric connection cables or conductors (not shown) are connected respectively to the said terminals by means of special connection lugs 99, for instance such as those forming the subject matter of US. Pat. No. 3,452,325. The said terminals are placed in the space comprised between the casing 94 and the contact-carrying block 88 and the connecting cables issue from the case through stuffing-boxes mounted in the orifice. 100 of the carter 14 communicating with the interior of the protecting casing 94.

In the chamber 93 of the contact-carrying block 88 are mounted four stationary contact elements, namely two contact elements 101 for the upper tier and two contact elements 102 for the lower tier, each of which isconnected to its respective terminal. In the chamber 93 are also provided two vertical hinge pins 103, 104 on each of which are mounted two rocking pawls 105,

106 corresponding respectively to the two contact tiers and carrying movable contact members 107, 108 adapted to co-operate with the stationary contact elements 101, 102. Each pawl is urged towards the contact closing position by an individual return spring 109 serving at the same time as a conductor for electric connection with a corresponding terminal.

The two aforesaid tiers of pawls are actuated respectively by two cams 110, 111 keyed respectively on the lower end of the lower shaft element 23. Each cam displaysa working profile comprising the shaped bosses 112, 113 adapted to co-operate alternativelywith one or the vother pawl of the associated tier, according to whether the cam turns in one or the other direction of rotation, determined by the direction of running on the railway. The said working profile is such that when one and the same cam comes into contact with the corresponding actuating heel of a pawl, the latter is actuated to open the contacts while the other pawl of the same tier is not actuated and is therefore in contactclosing position. The two superposed cams advantageously display working profiles which are inverted or substantially symmetrical with respect to a point on the common vertical axis of rotation, so that the pawls are always actuated in diagonal pairs, one diagonal pair of pawls being closed when the other diagonal pair is open and vice versa, so that the switch 16 constitutes an actual inverter or reversing switch. The'terminals are readily accessible, for it is sufficient to simply remove the casing 94 by disengaging its unremovable hooking or fastening clasps or catches 95.

The control lever 13 is advantageously designed in two pieces comprising in particular an end arm portion removably screwed onto the internal portion carrying the toothed segment.

The apparatus which has just been described an which necessitates pratically no adjustment or maintenance operates in the following manner, assuming initially the variousmembers of the apparatus to be positioned according to the configuration of FIG. 2, with the lever 13 in its central upper position of rest. When the saidlever is hit by the wheel of a rolling vehicle, it moves downward under the action of the impact along one or the other guiding slot 78, depending upon the direction of running of the vehicle. This downward motion produces, owing to the meshing of the toothed segment 48 with the rack 47, an ascending displacement of the piston 27 by overcoming the antagonistic action of the return springs 39, thus causing, in the dash-pot operating as a suction and forcing pump, the sucking of a certain quantity of oil 43 into the lower section 38 successively through the filter 55 and the sucking and check valves 54. Since the displacement of the lever 13 follows a downward oblique rectilinear trajectory, this motion of the lever 13 imparts through the medium of its hinge pin 49 a simultaneous motion of rotation of the movable assembly 17 about its vertical axis, thus causing the rotation of the switch cams 110, 111 of the switch, which cams then synchronously close and open specific electric circuits. The damping of the impact undergone by the lever 13 occurs in the carter 14 subsequent to the operation of the switch. When the control lever 13 reaches its downward travel end, the effect of percussion or impact ceases to be exerted thereon and the return springs 39 then push the piston 27 downwards. During this descending motion of the piston, the latter forces out the oil contained in the lower section 38 and this oil flows successively through the bore 25 of the lower shaft element 23 and penetrates through the hole 70 and the tube 68 into the escape channel 45 constituted by the bore of the piston rod where the oil flows upwardly about the thermostatic rod 71 and then passes through the calibrated adjutage adjusted by the needle 73, the pressurereducing chamber 67 and the pressure-reducing or limiting valve 59 which produce-a restriction to this flow of oil, thus slowing down the descending motion of the piston and, therefore, the return of the lever 13 to its normal upper position, as well as the attendant rotation, in the opposite direction, of the rotor shaft 17. The oil issuing from the valve 59 flows through the space 47 and the passageway 82 into the enclosed space 81 and returns into the cavity 40 of the carter by passing through the guiding slot 76 where it serves to lubricate the sliding contact between the latter and the control lever 13. In proximity to the downward stroke end, the peripheral slots 35 of the piston 27 become uncovered by penetrating into the widened transverse portion 36 of the cylindrical chamber 26 of the dashpot, so that the oil in the lower section 38 may rapidly escape upwardly by passing through the upper sealing gaskets 28 of the piston to penetrate into the upper section 37 and return into the cavity'l4 through the orifices 41 This rapid and abrupt escape suddenly accelerates the descending motion of the piston 27 under the action of the return springs 39, thus ensuring a rapid'ending of the return motion of the lever 13 to its initial upper position.

Of course, the invention is by no means limited to the form of embodiment described and illustrated, which has been given by way of example only. In particular, it comprises all the means constituting technical equivalents to the means described as well as their combinations, should the latter be carried out according to the spirit of the invention.

What is claimed is:

1. Electromechanical apparatus for detecting the running of railway vehicles of the type secured laterally to a rail of a railway and comprising a rotary electric switch, the substantially vertical rotor shaft of which is hinged by means of a substantially horizontal hinge pin to a reversible rotary pivoting control lever of the said rotor, the exposed long arm of which is intended to be hit by a wheel of a rolling vehicle and is guided positively so as to be displaceable obliquely downwardly from a normal upper position of rest, symmetrically with respect to a vertical plane perpendicular to the railway respectively for both mutually opposed directions of running, the said lever being in addition movably connected with the piston rod of an oil dash-pot retarding the automatic return of the said lever to its upper position, mounted vertically slidable in a cylindrical chamber of the said rotor shaft and pushed permanently by a coaxial helical return spring in the rising direction of the said lever, wherein the said lever is horizontal hinge pin of the latter, while the said return spring is composed of at least two concentric component helical springs wound respectively in mutually opposite directions, surrounding the said piston rod and hearing at one end against the end wall of the dashpot cylinder solid with the rotor shaft and at the other end against the said piston.

2. Apparatus according to claim 1, provided with an oil suction and non-return valve for the said dash-pot, the said piston of which is traversed axially by a closed escape-channel provided with a calibrated throttling orifice providing a substantially constant, fixed and selectively variable rate of flow by means of a regulating needle wherein a throttle valve provided with an obturating ball, loaded with a spring whose calibration is adjustable, and mounted in the said escape channel downstream of the said calibrated orifice. in the direction of the escape flow, the said suction valve or the said ball valve comprising means ensuring a small determined permanent escape.

3. Apparatus according to claim 2, wherein the means ensuring a small determined permanent escape consist of a conical or spherical annular bearing surface of the seat of the said valve provided with angularly spaced imprints forming substantially plane facets extending over the whole width of the said bearing surface.

4. Apparatus according to claim 2, wherein the said needle displays an evolutive longitudinal profile terminating the central rod of a thermostatic device known per se, mounted in the said escape channel and automatically regularizing the rate of flow of the fluid stream by way of differential compensation as a function of the thermal variations of the viscosity of the working hydraulic fluid.

5. Apparatus according to claim 2, wherein the piston of the said dash-pot is provided, on its peripheral lateral surface, with spaced escape slots opening at one end into the end face of the said piston which is on the side of the said return springs and extending in the direction of the opposite face over a length which is smaller than that of the said piston, so as to leave on the latter a smooth zone, while the bore of the said cylindri cal chamber widens towards its end located on the side opposite to that of the said return springs, at a short distance from the stroke end of the said piston pushed by the said springs so as to uncover the said slots to make them communicate with the spaces located respectively on either side of the said piston.

6. Apparatus according to claim 5, wherein the said piston is provided with a double peripheral sealing gasket or packing, the gasket of packing located on the side opposite the said return springs being provided with the said escape slots.

7. Apparatus according to claim 2, comprising the said tubular piston rod and a hollow rotor shaft rotatably mounted in a sealingly closed carter at least partially filled with oil, wherein the said rotor shaft is composed of two, respectively upper and lower, tubular shaft elements which are coaxially aligned, each traversed longitudinally by a central bore, the central bore of the said upper shaft element widening transversely at its lower portion into a cylindrical working chamber for the said dash-pot, the piston rod of which slides in the upper portion of the said bore provided in this wall with a lateral opening for the passage of the toothed segment meshing with the said rack, the 'said cylindrical chamber being divided transversely in a manner known per se by the said piston into two variable-volume sections, the upper section of which contains the said return springs and communicates permanently with the oil cavity of the said carter through at least one passage orifice in the chamber wall, located substantially in straddling relationship to thelevel of the liquid surface, while the lower section and end of the working chamber are closed by the said lower shaft element by an end flange forming the bottom of the said lower section and secured to the end of the said upper shaft element, the said lower section communicating permanently with the central longitudinal bore of the said piston rod forming an escape channel traversing it entirely. a

8. Apparatus according to claim 7, wherein the said flange is secured against the said upper shaft element by way of clamping in a counter-sunk recess by means of an annular cap-nut screwed onto the said upper shaft element, the said flange being provided with at least one said suction and non-retum valve, upstream of which a filter is mounted in the said cap-nut.

9. Apparatus according to claim 7, wherein the said escape valve and the said calibrated orifice are placed at the upper end of the escape channel constituted by the central bore of the said piston rod, which upper end communicates with the oil cavity of the said carter, which is closed at its top by a cover supporting the upper bearing of the said rotor shaft, while the said piston rod bore is prolonged downwardly below the said piston by a tube secured to the said piston rod, penetrating and extending with an annular play in the bore of the said lower shaft element possibly down to the vicinity of the lower end of the latter, all inlet orifices being provided in the portion of the said tube located inside the said lower shaft element and the said thermostatic device being secured, for instance screwed, in the lower end of the said tube and obturating the latter, so that the rod, provided with a needle of the said device extends up to the said calibrated orifice.

10. Apparatus according to claim 7, comprising an oil-purifying plug comprising a magnetic core mounted on the said carter and penetrating into the mass of oil.

11. Apparatus according to claim 7, comprising a plate provided with a forced guiding slot in the shape of a reversed V for the said control lever, and a sealing bellows for the passage of the said lever, the said plate and the said bellows being secured to the wall of the said carter and covering the passage opening provided for the said lever in the said carter wall, wherein the said bellows is secured outside with respect to the said plate, thus defining with the latter an enclosed space communicating permanently through passageways with the oil cavity of the said carter and in particular with the said lower shaft element penetrating into the said case and carrying therein the said cams.

I! k l 

1. Electromechanical apparatus for detecting the running of railway vehicles of the type secured laterally to a rail of a railway and comprising a rotary electric switch, the substantially vertical rotor shaft of which is hinged by means of a substantially horizontal hinge pin to a reversible rotary pivoting control lever of the said rotor, the exposed long arm of which is intended to be hit by a wheel of a rolling vehicle and is guided positively so as to be displaceable obliquely downwardly from a normal upper position of rest, symmetrically with respect to a vertical plane perpendicular to the railway respectively for both mutually opposed directions of running, the said lever being in addition movably connected with the piston rod of an oil dash-pot retarding the automatic return of the said lever to its upper position, mounted vertically slidable in a cylindrical chamber of the said rotor shaft and pushed permanently by a coaxial helical return spring in the rising direction of the said lever, wherein the said lever is hinged at an intermediate point to the said rotor shaft and its movable connection with the said piston rod is ensured by the meshing of a vertical rack, solid with the said piston rod, with a mating toothed segment solid with the short arm of the said lever and centered on the horizontal hinge pin of the latter, while the said return spring is composed of at least two concentric component helical springs wound respectively in mutually opposite directions, surrounding the said piston rod and bearing at one end against the end wall of the dash-pot cylinder solid with the rotor shaft and at the other end against the said piston.
 2. Apparatus according to claim 1, provided with an oil suction and non-return valve for the said dash-pot, the said piston of which is traversed axially by a closed escape-channel provided with a calibrated throttling orifice providing a substantially constant, fixed and selectively variable rate of flow by means of a regulating needle wherein a throttle valve provided with an obturating ball, loaded with a spring whose calibration is adjustable, and mounted in the said escape channel downstream of the said calibrated orifice in the direction of the escape flow, the said suction valve or the said ball valve comprising means ensuring a small determined permanent escape.
 3. Apparatus according to claim 2, wherein the means ensuring a small determined permanent escape consist of a conical or spherical annular bearing surface of the seat of the said valve provided with angularly spaced imprints forming substantially plane facets extending over the whole width of the said bearing surface.
 4. Apparatus according to claim 2, wherein the said needle displays an evolutive longitudinal profile terminating the central rod of a thermostatic device known per se, mounted in the said escape channel and automatically regularizing the rate of flow of the fluid stream by way of differential compensation as a function of the thermal variations of the viscosity of the working hydraulic fluid.
 5. Apparatus according to claim 2, wherein the piston of the said dash-pot is provided, on its peripheral lateral surface, with spaced escape slots opening at one end into the end face of the said piston which is on the side of the said return springs and extending in the direction of the opposite face over a length which is smaller than that Of the said piston, so as to leave on the latter a smooth zone, while the bore of the said cylindrical chamber widens towards its end located on the side opposite to that of the said return springs, at a short distance from the stroke end of the said piston pushed by the said springs so as to uncover the said slots to make them communicate with the spaces located respectively on either side of the said piston.
 6. Apparatus according to claim 5, wherein the said piston is provided with a double peripheral sealing gasket or packing, the gasket of packing located on the side opposite the said return springs being provided with the said escape slots.
 7. Apparatus according to claim 2, comprising the said tubular piston rod and a hollow rotor shaft rotatably mounted in a sealingly closed carter at least partially filled with oil, wherein the said rotor shaft is composed of two, respectively upper and lower, tubular shaft elements which are coaxially aligned, each traversed longitudinally by a central bore, the central bore of the said upper shaft element widening transversely at its lower portion into a cylindrical working chamber for the said dash-pot, the piston rod of which slides in the upper portion of the said bore provided in this wall with a lateral opening for the passage of the toothed segment meshing with the said rack, the said cylindrical chamber being divided transversely in a manner known per se by the said piston into two variable-volume sections, the upper section of which contains the said return springs and communicates permanently with the oil cavity of the said carter through at least one passage orifice in the chamber wall, located substantially in straddling relationship to the level of the liquid surface, while the lower section and end of the working chamber are closed by the said lower shaft element by an end flange forming the bottom of the said lower section and secured to the end of the said upper shaft element, the said lower section communicating permanently with the central longitudinal bore of the said piston rod forming an escape channel traversing it entirely.
 8. Apparatus according to claim 7, wherein the said flange is secured against the said upper shaft element by way of clamping in a counter-sunk recess by means of an annular cap-nut screwed onto the said upper shaft element, the said flange being provided with at least one said suction and non-return valve, upstream of which a filter is mounted in the said cap-nut.
 9. Apparatus according to claim 7, wherein the said escape valve and the said calibrated orifice are placed at the upper end of the escape channel constituted by the central bore of the said piston rod, which upper end communicates with the oil cavity of the said carter, which is closed at its top by a cover supporting the upper bearing of the said rotor shaft, while the said piston rod bore is prolonged downwardly below the said piston by a tube secured to the said piston rod, penetrating and extending with an annular play in the bore of the said lower shaft element possibly down to the vicinity of the lower end of the latter, all inlet orifices being provided in the portion of the said tube located inside the said lower shaft element and the said thermostatic device being secured, for instance screwed, in the lower end of the said tube and obturating the latter, so that the rod, provided with a needle of the said device extends up to the said calibrated orifice.
 10. Apparatus according to claim 7, comprising an oil-purifying plug comprising a magnetic core mounted on the said carter and penetrating into the mass of oil.
 11. Apparatus according to claim 7, comprising a plate provided with a forced guiding slot in the shape of a reversed V for the said control lever, and a sealing bellows for the passage of the said lever, the said plate and the said bellows being secured to the wall of the said carter and covering the passage opening provided for the said lever in the said carter wall, wherein the said belloWs is secured outside with respect to the said plate, thus defining with the latter an enclosed space communicating permanently through passageways with the oil cavity of the said carter and in particular with the upper end of the said escape channel, above the said escape valve.
 12. Apparatus according to claim 7, equipped with the said electric switch comprising rocking contact pawls actuated by one or several cams mounted on the said rotor shaft, wherein the sealed case, provided with a protecting hood, of the said switch is secured hermetically and removably under the said carter against the bottom of the latter which is traversed sealingly by the said lower shaft element penetrating into the said case and carrying therein the said cams. 